The Brandenburg Gate
Berlin, Germany
The gate was made more famous during The Cold War as it was located along the dividing Berlin Wall, once the wall fell the gate became the symbol of unified Germany.
http://www.listal.com/list/the-iron-curtain

This could quite easily become a very long list, so the buildings featured are mainly known throughout the globe or famous for a significant reason. I however would like suggestions and ideas from you guys to make the list as complete as possible so please post any suggestions in the comments below.